1. Field of the Invention
The present invention relates to eyeglasses in which a lens is exchangeable.
2. Description of the Related Art
A conventional example of this type of eyeglasses is shown in FIGS. 11 and 12, which is disclosed in U.S. Pat. No. 4,824,233. This example is designed as a pair of sunglasses and includes a transparent curved plate-shaped lens 21, a frame 22 having the length covering the entire upper edge of the lens 21 and fittingly receiving the lens 21 therein, and temples 23 foldably attached to respective left and right ends of the frame 22.
However, since the pair of eyeglasses described above includes the frame 22 having the length covering the entire upper edge of the lens 21, this frame 22 disadvantageously increases the volume and weight of the eyeglasses. Further, the frame 22 narrows the forward vision of a wearer of the eyeglasses. In particular, in case the wearer leans forward, for example, in riding on a bicycle, the wearer has difficulty looking forward.
Another example of this type of eyeglasses is shown in FIGS. 13 and 14, which is disclosed in the Japanese Patent Application, Publication No. H06-175085 A1. This example is designed as a pair of sunglasses, and includes a flexible, elastic single lens 31 having an appropriate curved surface, a couple of left and right frames 32 respectively fixed to the upper edges of the respective side end portions of the lens 31, and temples 33 attached to the respective frames 32. The upper edge portions of the respective side end portions of the lens 31 have threaded holes (not shown) for screws, and the frames 32 are detachably fixed to the lens 31 with screws 34.
In the eyeglasses described above, the structure in which the frames 32 are detachably fixed to the upper edges of the respective side end portions of the lens 31 with the screws 34 provides sufficient fixing strength but requires time and labor in assembling. In practice, although a lens is detachably fixed, it is not easily detached and attached, and exchanging lenses is troublesome.